The overall objectives are to define the roles played by thyroid hormones, their deficiency, and prolactin in human breast cancer. Attention will be paid to the influence of these factors on the prognosis of breast cancer, and on changes produced in hypothalamo-pituitary-thyroid and prolactin activity by adjuvant chemohormonal therapy for stage II disease. These objectives will be met by (I) a study of triiodothyronine, prolactin and estrogen receptors, and mitochondrial alpha-glycerophosphate dehydrogenase activity in human breast cancer tissues, and the influence of prior hyperprolactinemia on these proteins, and (II) studies of basal plasma TRH, TSH and prolactin levels, and responses to TRH stimulation before and at intervals during adjuvant chemohormonal therapy. The hormonal moieties in these combined regimens will include an anti-estrogen, androgen and corticosteroid.